Manufacturing Method of Semiconductor Device

ABSTRACT

A management method is able to quickly investigate the cause of a defect generated in a semiconductor product manufacturing process. Manufacturing conditions in various QFP manufacturing steps are stored in a main server while correlating them with an identification number of the QFP, and a two-dimensional bar code corresponding to the identification number is stamped to the surface of the QFP. In the event of occurrence of a defect of the QFP, the manufacturing conditions for the QFP stored in the main server can be traced in an instant by reading the two-dimensional bar code of the QFP and thereby specifying the identification number.

CROSS-REFERENCE TO RELATED APPLICATIONS

The disclosure of Japanese Patent Application No. 2009-217825 filed onSep. 18, 2009 including the specification, drawings and abstract isincorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

The present invention relates to a manufacturing method of asemiconductor device. Particularly, the present invention is concernedwith a semiconductor manufacturing technique capable of quicklyinvestigating the cause of a defect generated in a semiconductor devicemanufacturing process.

The semiconductor device manufacturing process broadly comprises apre-process (wafer process) in which integrated circuits are formed on amain surface (integrated circuit-forming surface) of a semiconductorwafer, e.g., a single crystal silicon wafer, by combiningphotolithography technique, CVD technique, sputtering technique andetching technique and a post-process (assembling process) in which thesemiconductor wafer formed with the integrated circuits is diced into aplurality of semiconductor chips and then the semiconductor chips areeach sealed into a package, e.g., a resin or ceramic package.Semiconductor device manufacturers make management of products byindicating product information such as, for example, product model name,customer logo mark and production code on the surface of eachsemiconductor product (semiconductor package) manufactured through theabove processes.

Patent Document 1 (Japanese Unexamined Patent Publication No. Hei 11(1999)-008327) discloses a semiconductor chip identification puttingmethod which permits management of each of plural semiconductor chipseven after separation of the semiconductor chips from a semiconductorwafer by dicing.

More particularly, first with respect to plural semiconductor chipsformed on a semiconductor wafer, wafer number and intra-wafer chippositions are determined as chip identification codes. Next, when thesemiconductor chips thus given chip identification codes are separatedfrom the semiconductor wafer by dicing and mounted onto a lead frame, abar code corresponding to the above identification code of each of thesemiconductor chips is affixed to a lead frame portion located near thesemiconductor chip. This bar code is read by a bar code reader, thenafter assembly of an IC package, a bar code corresponding to the barcode read by the bar code reader is affixed to the back surface of theIC package. According to this semiconductor chip identification codeputting method, even after assembly of the IC package, the manufacturinglot number and wafer number of the semiconductor chip incorporated inthe IC package can be recognized by reading the bar code affixed to thepackage back surface. Consequently, it becomes possible to make afollow-up survey of, for example, conditions in the manufacturing stage.

Patent Document 2 (Japanese Unexamined Patent Publication No.2004-022981) discloses a technique for indicating externally visibleproduct information on both a package surface and a back surface of eachchip mounting portion of a lead frame in a product wherein the chipmounting portion is exposed from the package back surface, like QFN(Quad Fat No lead package) or TSSOP (Thin Shrink Small Outline Package)out of small-sized semiconductor packages. According to Patent Document2, pieces of product information low in commonness between producttypes, such as, for example, customer logo mark, product model name,product code and lot trace code, are indicated on the package surface,while pieces of product information high in commonness between productssuch as, for example, manufacturing nation code are indicated on theback surface of the chip mounting portion. The product information onthe package surface is formed by printing, sealing or laser markingafter package molding, while the product information on the back surfaceof the chip mounting portion is formed in advance by pressing or etchingbefore start of package assembly.

SUMMARY OF THE INVENTION

As noted above, semiconductor device manufacturers make management ofproducts by indicating product information on the surface of asemiconductor product (semiconductor package) as a completed product.

In recent years, however, the types of semiconductor products arediversified and semiconductor product manufacturing steps are alsodiversified and complicated, so in the event of occurrence of a defectof a semiconductor product, it is difficult for the conventional productmanagement methods to quickly investigate the cause of the defect.

For example, in Patent Document 1, a follow-up survey of manufacturingconditions in the pre-process is made possible by putting asemiconductor chip identification code in the form of a bar code to theback surface of the semiconductor package. This identification codecannot be utilized in the follow-up survey for investigating the causeof a defect developed in the post-process because it does not containany information on manufacturing conditions in the post-process(assembling process).

It is an object of the present invention to provide a management methodcapable of quickly investigating the cause of a defect of asemiconductor product.

The above and other objects and novel features of the present inventionwill become apparent from the following description and the accompanyingdrawings.

The following is an outline of one embodiment in accordance with thepresent invention.

In one preferred aspect of the present invention there is provided amanufacturing method of a semiconductor device, comprising the steps of(a) providing a base member, the base member including a device areahaving a chip mounting portion and an outer frame portion positionedoutside the device area, (b) after the step (a), putting a firstidentification number to the outer frame portion of the base member, (c)after the step (b), mounting a semiconductor chip over the chip mountingportion of the base member, (d) after the step (c), sealing thesemiconductor chip with resin such that the outer frame portion isexposed, and forming a sealing body, and (e) after the step (d), readingthe first identification number and putting first intra-serverinformation corresponding to the read first identification number, outof a plurality of pieces of intra-server information stored in a server,as a second identification number, to the sealing body.

The following is a brief description of an effect obtained by thetypical invention out of the inventions disclosed herein.

According to the preferred aspect of the present invention, conditionsfor manufacturing a semiconductor package stored in a computer can betraced in an instant by reading a bar code affixed to the surface of thesemiconductor package, so that it is possible to take an anti-defectmeasure quickly.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an entire flow chart showing a manufacturing process for a QFPaccording to a first embodiment of the present invention;

FIG. 2 is an entire plan view of a lead frame used in manufacturing theQFP;

FIG. 3 is an entire plan view of a semiconductor wafer used inmanufacturing the QFP;

FIG. 4 is a plan view of the lead frame, showing an ID stamping step;

FIG. 5 is a plan view of the lead frame, showing another example of anID stamping step;

FIG. 6 is a plan view of the lead frame, showing a step of supplying anadhesive to surfaces of die pad portions;

FIG. 7 is a plan view of the lead frame, showing a die bonding step;

FIG. 8 is a plan view of the lead frame, showing another example of adie bonding step;

FIG. 9 is a partially enlarged plan view of the lead frame, showing awire bonding step;

FIG. 10 is a plan view of the lead frame, showing a molding step;

FIG. 11 is a partially enlarged plan view of the lead frame, showing atiebar cutting step;

FIG. 12 is a plan view of the lead frame, showing a laser marking step;

FIGS. 13( a) and 13(b) are diagrams showing a method for stamping atwo-dimensional bar code onto a surface of molding resin, of which FIG.13( a) is a side view of the lead frame as seen in a direction parallelto a moving direction of the lead frame and FIG. 13( b) is a side viewas seen in a direction orthogonal to the lead frame moving direction;

FIG. 14 is a plan view of the lead frame, showing another example of alaser marking step;

FIG. 15 is a partially enlarged plan view of the lead frame after anexterior plating step;

FIG. 16 is a plan view showing a sealing body after a lead frame cuttingstep;

FIG. 17 is a sectional view showing a completed state of the QFP;

FIG. 18 is an entire flow chart showing a manufacturing process for aCSP according to a second embodiment of the present invention;

FIG. 19 is an entire plan view showing a surface of a map substrate usedin manufacturing the CSP;

FIG. 20 is an entire plan view showing a back surface of the mapsubstrate used in manufacturing the CSP;

FIG. 21 is a plan view of the map substrate, showing an ID stampingstep;

FIG. 22 is a plan view of the map substrate, showing a die bonding step;

FIG. 23 is a partially enlarged plan view of the map substrate, showinga wire bonding step;

FIG. 24 is a plan view of the map substrate, showing a molding step;

FIG. 25 is a plan view of the map substrate, showing a laser markingstep;

FIG. 26 is a plan view of the map substrate, showing another example ofa laser marking step;

FIG. 27 is a partial sectional view of the map substrate, showing a ballmounting step; and

FIG. 28 is a sectional view showing a completed state of the CSP.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention will be described below in detailwith reference to the drawings. In all the drawings for illustrating theembodiments, members having the same functions are identified by thesame reference numerals, and repeated explanations thereof will beomitted. In the following embodiments, explanations of the same orsimilar portions will not be repeated in principle except where suchexplanations are specially needed. Further, in the drawings forillustrating the following embodiments, even a plan view may be enlargedto facilitate understanding of the illustrated configuration.

First Embodiment

In this embodiment the present invention is applied to the manufactureof a QFP (Quad Flat Package) which is a kind of a semiconductor package.FIG. 1 is an entire flow chart showing a manufacturing process for theQFP.

For manufacturing the QFP, first a lead frame shown in FIG. 2 and asemiconductor wafer shown in FIG. 3 are provided as base members (chipmounting members).

<On Lead Frame>

The lead frame LF shown in FIG. 2 is formed of copper (Cu) or copperalloy and comprises a plurality of device areas (areas which will becomesemiconductor devices) and an outer frame portion 8 positioned outsidethe device areas. Each device area includes a chip mounting area (diepad, chip mounting portion) 4 as a portion for mounting a semiconductorchip, a plurality of leads 5 formed around the chip mounting area 4, aplurality of suspending leads 6 formed integrally with the chip mountingarea 4, and tiebars 7 formed integrally with both leads 5 and suspendingleads 6. The leads 5, suspending leads 6 and tiebars 7 are supported bythe outer frame portion 8. The chip mounting area 4 is supported by theouter frame portion 8 through the suspending leads 6.

The actual lead frame is provided with a large number of die pads 4, buthere the lead frame LF provided with three device areas is illustratedfor making the drawings easier to see. That is, since the lead frame LFis of a structure for mounting three semiconductor chips, three QFPs canbe obtained from one lead frame LF.

Although the lead frame LF used in this embodiment is formed of copperor copper alloy, it may be formed of an iron-based metal.

<On Semiconductor Wafer>

A semiconductor wafer 1A shown in FIG. 3 is in a state after completionof a pre-process and a subsequent dicing step. It is in a divided stateinto a large number of semiconductor chips 1. In this embodiment, asshown in FIG. 3, plural semiconductor chips 1 are formed in a matrixshape in relation to a notch formed in a peripheral edge portion of thesemiconductor wafer 1A. The aforesaid pre-process includes a pluralityof steps of forming an integrated circuit on each of the semiconductorchips 1 of the semiconductor wafer 1A by combining photolithographytechnique, CVD technique, sputtering technique and etching technique andfurther includes an electrical characteristic checking step ofcontacting a probe with a surface of each bonding pad 2 formed on themain surface of each semiconductor chip 1 and determining whether theconstituent elements of the integrated circuit are good or not andwhether each wiring line for coupling between elements is conductive ornot.

According to this embodiment, in the pre-process there is prepared achip identification number (ID) for each semiconductor chip, including aproduction lot number of the semiconductor wafer 1A, a semiconductorwafer number, the position of the semiconductor chip 1 concerned in thesemiconductor wafer 1A, and information as to whether the semiconductorchip 1 is non-defective or defective, then after receipt of thesemiconductor wafer 1A in the post-process, the chip identificationnumber is stored in a server (a wafer map data management server WS).Thus, by making reference to the wafer map data management server (WS)it is possible to easily specify in which production lot eachsemiconductor chip 1 was manufactured and on which semiconductor wafer1A and in which position it was located.

Next, with reference to the entire flow chart of FIG. 1 and also toFIGS. 4 to 17, the QFP manufacturing method of this embodiment will bedescribed step by step.

<ID Stamping Step>

First, a predetermined number of lead frames LF shown in FIG. 2 areprovided. Then, in each lead frame LF, as shown in FIG. 4, anidentification number (ID) for identifying the lead frame LF is affixedto a surface (upper surface, main surface) of an outer frame portion 8positioned outside the device areas of each lead frame LF. Theidentification number (ID) used in this embodiment is a two-dimensionalcode (BC1). For example, if the number of provided lead frames LF is100, the numerals 00, 01, . . . , 99 are stamped in order in the form ofa two-dimensional code (BC1) to those lead frames LF.

The two-dimensional bar code (BC1) is a bar code having information intwo longitudinal and lateral directions and is characteristic in thatthe amount of information capable of being recorded is extremely largeas compared with a one-dimensional bar code having information in onlyone direction. Moreover, since the two-dimensional bar code can bereduced in area as compared with a one-dimensional bar code, it can bestamped also to the surface of a lead frame LF having a narrow outerframe portion 8. In the case where the area of the outer frame portion 8of each lead frame LF is sufficiently wide, a one-dimensional bar codemay be stamped in place of the two-dimensional bar code (BC1).

By thus stamping the identification number of each lead frame LF in theform of a bar code to the surface of the lead frame LF it is possible toautomate the specifying of the lead frame identification number.

A leaser beam is used for stamping the two-dimensional bar code (BC1) tothe surface of the lead frame LF. A laser used in this embodiment isrequired to satisfy the conditions of a power of 160 W to 170 W, a pulsegenerating frequency (Qsw) of 27 to 35 kHz, and a polygon mirrorrevolutions of 100 to 120 rpm. Particularly, in the case where each leadframe LF is formed of copper (Cu) or copper alloy, it is preferable touse a laser beam (so-called green laser beam) having a wavelength of 532nm or so. Since the green laser beam is high in its absorptance forcopper as compared with laser beams of other wavelengths (e.g., infraredlight with a wavelength of about 1064 nm), it is easy to control thelaser output. Therefore, by using the green laser beam, thetwo-dimensional bar code (BC1) can be stamped with high accuracy to thesurface of each lead frame LF. Besides, the contamination of the leadframe surface is diminished because the amount of dust particlesproduced from the surface of each lead frame LF during stamping can bedecreased.

At the time of stamping the two-dimensional bar code (BC1) to each leadframe LF, in order to prevent the two-dimensional bar code (BC1) frombeing damaged and becoming incapable of being read in a subsequentmanufacturing step, the same two-dimensional bar codes (BC1) may bestamped to plural positions of an outer frame portion 8 as shown in FIG.5.

Next, using a bar code reader (RO) shown in FIG. 1, the two-dimensionalbar code (BC1) stamped to each lead frame LF is read and theidentification number thus read is stored in a server (a lead frame mapdata management server LS). Now, in the lead frame map data managementserver (LS), preparations are completed for recording each stepconditions applied to the base member corresponding to eachidentification number.

Further, an appearance check of each lead frame LF is performed by imagerecognition using a camera (CO) to check whether there is a defect(e.g., loss or deformation of leads 5). In the event a defect should bedetected, there is made correlation between the identification number ofthe lead frame LF concerned and the defective portion, then theinformation thus obtained is stored in the lead frame map datamanagement server (LS).

<Die Bonding Step>

Next, the lead frame LF with the two-dimensional bar code (BC1) stampedthereon is conveyed to a die bonder (a die bonding apparatus) which isused in a die bonding step. Then, as shown in FIG. 6, an adhesive 9 issupplied to the surface of each chip mounting area (die pad, chipmounting portion) 4 on the lead frame LF. Thereafter, as shown in FIG.7, the semiconductor chips 1 obtained from the semiconductor wafer 1Ashown in FIG. 3 are picked up one by one and mounted onto die pads 4respectively. That is, each semiconductor chip 1 is mounted onto eachchip mounting area 4 through the adhesive 9.

For mounting each semiconductor chip 1 onto each chip mounting area 4 ofthe lead frame LF, there is made alignment between the semiconductorchip 1 and the associated die pad 4 with use of a position recognizingcamera (C1) shown in FIG. 1. Then, the two-dimensional bar code (BC1)stamped to the lead frame LF is read using recognition means (bar codereader R1), and information (identification number) corresponding to thelead frame LF recognized by the bar code reader (R1) in the die bonder(die bonding apparatus) out of the pieces of information (pieces ofintra-server information) stored in the server (read frame map datamanagement server LS) in a previous step (here the ID stamping step) isdrawn out from the interior of the server. Next, a check is made to seeif there is any defect in part of the recognized lead frame LF. If thereis any defect in part of the lead frame LF with the identificationnumber in question assigned thereto (for example, if there is a loss ordeformation in the chip mounting area 4), the semiconductor chip 1 isnot mounted onto the chip mounting area 4 located at the portion (thecentral portion in this example) including the defect, as shown in FIG.8.

For mounting each semiconductor chip 1 onto each of the chip mountingareas 1 of the lead frame LF, reference is made to the identificationinformation of the semiconductor chip 1 concerned which is stored in thewafer map data management server (WS) and a check is made to see if thesemiconductor chip 1 corresponding to that identification information isa non-defective product or a defective product. If the semiconductorchip 1 concerned is a defective product, it is not mounted onto the chipmounting area 4.

Next, there is made correlation between the identification number of thelead frame LF obtained from the two-dimensional bar code (BC1) and theidentification number of the semiconductor chip 1 mounted on the leadframe LF and the information thus obtained (updated intra-serverinformation) is stored in a server (main server MS). Further, there ismade correlation between the conditions (manufacturing conditions: e.g.,model number of the die bonding apparatus used and the type of theadhesive 9) used when the semiconductor chip 1 was mounted onto the diepad 4 of the lead frame LF and the identification number of the leadframe LF, and the information thus obtained is stored in the main server(MS).

In this way the semiconductor chip 1 is mounted onto each die pad 4 oneach lead frame LF, correlation is made between the identificationnumber of each lead frame LF and that of each semiconductor chip mountedon the lead frame LF, and the information thus obtained is stored in themain server (MS). Further, there is made correlation between theconditions used when the semiconductor chip 1 was mounted onto each diepad 4 on each lead frame LF and the identification number of each leadframe LF, and the information thus obtained is stored in the main server(MS).

Thereafter, each lead frame LF is put into a single wafer baking ovenand the adhesive 9 is heat-cured to fix the semiconductor chips 4 ontothe die pads 4 respectively.

<Wire Bonding Step>

Next, each lead frame LF having gone through the die bonding step isconveyed to a wire bonder (wire bonding apparatus) used in a wirebonding step. Then, using a position recognizing camera (C2) shown inFIG. 1, the lead frame LF is positioned onto a stage of the wire bondingapparatus and thereafter, as shown in FIG. 9 (a partially enlarged planview of the lead frame LF), bonding pads 2 of each semiconductor chip 1and leads 5 are coupled together electrically through conductive members3. The conductive members used in this embodiment are gold (Au) wires.

Then, the two-dimensional bar code (BC1) stamped to the lead frame LF isread using recognition means (bar code reader R2), and information(identification number) corresponding to the lead frame LF which hasbeen recognized by the bar code reader (R2) in the wire bonder (wirebonding apparatus), out of the plural pieces of base member information(pieces of intra-server information) which were stored in the server(lead frame map data management server LS) in a previous step, is drawnout from the interior of the server. Then, a check is made to see ifthere is a defect in part of the recognized lead frame LF. As a result,if a defect is found in part of the lead frame LF with the saididentification number assigned thereto, wires 3 are not bonded to theportion including the defect.

Next, there is made correlation between bonding conditions for the wires3 (manufacturing conditions: e.g., model number of the wire bondingapparatus used and the diameter of each wire 3) and the identificationnumber of the lead frame LF obtained from the two-dimensional bar code(BC1), and the information (updated intra-server information) thusobtained is stored in the server (main server MS).

In this way bonding pads of each semiconductor chip mounted on each leadframe LF and the leads 5 are coupled together electrically, thencorrelation is made between the bonding conditions for the wires 3 andthe identification number of each lead frame LF, and the informationthus obtained is stored in the server (main server MS).

Thereafter, an appearance check for each lead frame LF is performed tocheck the wires 3 for breaking or short-circuit. In the event a defectshould be detected, the identification number of the associated leadframe LF obtained from the two-dimensional bar code (BC1) and thedetective portion are correlated with each other and the informationthus obtained is stored in the lead frame map data management server(LS).

<Molding Step>

The lead frame LF having gone through the wire bonding step (or theappearance checking step) is then conveyed into a molding apparatus(mold) used in a molding step (resin sealing step). Then, the lead frameLF is disposed within a mold (not shown) of the molding apparatus andthe two-dimensional bar code (BC1) stamped to the lead frame LF is readusing recognition means (bar code reader R3) in the molding apparatus ifnecessary. Further, the information (identification number)corresponding to the lead frame LF recognized by the bar code reader R3in the molding apparatus, out of the pieces of base member information(pieces of intra-server information) which were stored in the server(lead frame map data management server LS) in a previous step, is drawnout from the interior of the server. Then, as shown in FIG. 10, thesemiconductor chip 1, wires 3, chip mounting area (die pad) 4, portions(inner leads) of the leads 5 and portions of the suspending leads 6 aresealed with resin (molding resin) to form a sealing body (resin sealingbody) 10. In this case, the device area (the semiconductor chip 1mounted in the device area) is sealed with resin such that theidentification number (ID, two-dimensional bar code BC1) formed on theouter frame portion 8 is exposed to the exterior of the sealing body 10.Further, the resin filling performance is monitored using a camera (C3)shown in FIG. 1.

Next, the two-dimensional bar code (BC1) stamped to the lead frame LF isread using the bar code reader (R3), thereafter, correlation is madebetween molding conditions (manufacturing conditions: e.g., model numberof the molding apparatus used and the kind of the sealing body 10) andthe identification number of the lead frame LF obtained from thetwo-dimensional bar code (BC1), and the information thus obtained(updated intra-server information) is stored in the server (main serverMS).

In this way each lead frame LF is loaded to the mold of the moldingapparatus and each semiconductor chip 1, wires 3, chip mounting area(die pad) 4, portions (inner leads) of the leads 5 and portions of thesuspending leads 6 are sealed with resin. Further, there is madecorrelation between the molding conditions and the identification numberof each lead frame LF, and the information thus obtained is stored inthe main server (MS).

<Tiebar Cutting Step>

Next, as shown in FIG. 11, tiebars 7 of the lead frame LF, which barsare exposed to the exterior of the sealing body 10, are cut to separatethe leads (outer leads) 5 electrically from one another. The tiebars 7are for preventing resin leakage to the exterior from the area where thesealing body 10 is formed in the previous resin sealing step. In thistiebar cutting step, the state of cutting is monitored using a camera(C4) shown in FIG. 1.

Then, the two-dimensional bar code (BC1) stamped to the lead frame LF isread using recognition means (bar code reader R4), thereafter,correlation is made between cutting conditions (manufacturingconditions: e.g., model number of the cutter used) for the tiebars andthe identification number of the lead frame obtained from thetwo-dimensional bar code (BC1), and the information (updatedintra-server information) thus obtained is stored in the server (mainserver MS).

In this way the tiebars 7 of each lead frame LF are cut and there ismade correlation between the cutting conditions for the tiebars and theidentification number of the lead frame LF, then the information thusobtained is stored in the main server (MS).

Subsequently, each lead frame LF is put into a single wafer baking ovenand the constituent resin of the sealing body 10 is cured completely.

<Laser Marking Step>

Next, the lead frame LF having gone through the molding step (or thebaking process) is conveyed to an apparatus used in a laser marking stepand a two-dimensional bar code (BC2) is stamped to the surface of eachsealing body 10 formed on the lead frame LF.

In this two-dimensional bar code (BC2) forming step, first thetwo-dimensional bar code (BC1) stamped at a portion (outer frame portion8) outside the device area of the base member (lead frame LF) is readusing recognition means (bar code reader R5) in the laser markingapparatus. Then, information (e.g., intra-server information, chipposition information, wafer production lot number, semiconductor wafernumber, assembly lot number, product model name) corresponding to thelead frame LF recognized by the bar code reader (R5) in the lasermarking apparatus, out of the pieces of base member information (piecesof intra-server information) which were stored in the server (lead framemap data management server LS) in a previous step, is drawn out from theinterior of the server. Next, this drawn-out information is formed as anew identification number (two-dimensional bar code BC2) on the surfaceside of the sealing body 10.

As to the information to be stored in the two-dimensional bar code (BC2)formed on the surface of the sealing body, it is possible to selectivelycall information managed by the server and let it be stored in thetwo-dimensional code (BC2), with no limitation being made to the saidinformation. Therefore, the information stored in the two-dimensionalbar code (BC2) may be the same information as the two-dimensional barcode (BC1) stamped to the outer frame portion 8 of the lead frame LF. Inthis case, by collating information of the corresponding base member(lead frame LF) from among the pieces of base member information whichhave been stored in the lead frame map data management server (LS),after identification by the bar code reader, it is possible to draw outthe aforesaid various pieces of information. In this embodiment,conditions of the laser used in the laser marking step are the same asthose used in the ID stamping step, but no limitation is made thereto.

FIGS. 13( a) and 13(b) are diagrams showing a method for stamping thetwo-dimensional bar code (BC2), of which FIG. 13( a) is a side view asseen in a direction parallel to the moving direction of the lead frameLF and FIG. 13( b) is a side view as seen in a direction orthogonal tothe moving direction of the lead frame LF. In these figures, the numeral11 denotes a guide rail of the laser marking apparatus and numeral 12denotes a conveyance pawl.

For stamping the two-dimensional bar code (BC2) to the surface of thesealing body 10 formed on the lead frame LF, first the two-dimensionalbar code (BC1) stamped to the outer frame portion 8 of the lead frame LFis read with use of the bar code reader (R5) to specify theidentification number of the lead frame LF. As shown in FIG. 13, whenholding and conveying the lead frame LF with the guide rails 11, onlythe lower surface of the lead frame LF is held, so by disposing the barcode reader (R5) above the lead frame LF it is possible to read thetwo-dimensional bar code (BC1) easily. When reading the two-dimensionalbar code (BC1) by the bar code reader (R5), it is preferable to stop theguide rails 11 or allow the lead frame LF to move at a low speed.

Next, laser beam LB is radiated to the surfaces of the sealing bodies 10in a successive manner to stamp to each of the surfaces atwo-dimensional bar code (BC2) corresponding to the identificationnumber of the lead frame LF concerned. In this embodiment, though notshown, marks of product information (e.g., product model name, customerlogo mark, production code) are also stamped to the surface of eachsealing body at the time of stamping the two-dimensional code (BC2)thereto. By so doing, the marking step can be done as a single step andhence it is possible to simplify the manufacturing process.

When stamping the two-dimensional bar code (BC2) and marks, reference ismade to the lead frame map data management server (LS) to check whethera defect has occurred in part of the lead frame LF concerned in thesteps so far gone through. If a defect has occurred in part of the leadframe LF, the two-dimensional bar code (BC2) and marks are not stampedto the surface of the sealing body 10 which includes the defect (thecentral sealing body in the illustrated example), as shown in FIG. 14.Although in this embodiment a reference has been made above to anexample of forming the two-dimensional bar code (BC2) on the surfaceside of each sealing body 10, the bar code in question may be formed onthe back surface side of the sealing body 10.

Next, using a camera (C5), a check is made to see if the two-dimensionalcode (BC2) and marks have surely been stamped or not, and the result isstored in the main server (MS) while correlating it with theidentification number of the lead frame LF concerned.

<Exterior Plating Step>

Next, the lead frame LF after completion of the above stamping of thetwo-dimensional bar code (BC2) and marks is immersed in an electrolyticplating tank to form a plating layer (plating film) comprising so-calledlead-free solder (the lead (Pb) content is prescribed to be 1000 ppm(0.1 wt %) or less in RoHS Instructions) on the surface of the leadframe LF exposed to the exterior of the sealing body 10. The material ofthe lead-free solder in this embodiment is tin (Sn) or an alloycontaining tin (Sn) as a principal component, more specifically, tin(Sn)-bismuth (Bi) alloy.

As a result of the exterior plating there is formed a plating layer alsoon the surface of the two-dimensional bar code (BC1) stamped to theouter portion 8 of the lead frame LF, resulting in deposition of theplating layer within grooves of the two-dimensional bar code (BC1)stamped to the outer frame portion 8 of the lead frame LF, as shown inFIG. 15. Consequently, it becomes difficult for the bar code reader torecognize the two-dimensional bar code (BC1) which has been formed onthe outer frame portion 8.

In this embodiment, however, prior to the exterior plating step, thetwo-dimensional code (BC2) is stamped to the surface of each sealingbody 10 on the basis of the two-dimensional bar code (BC1) stamped tothe outer frame portion 8 and the information stored in the lead framemap data management server (LS), so that it is possible to avoid theabove-mentioned inconvenience.

Moreover, in case of forming the two-dimensional bar code (BC2) forexample by an ink marking method, there is a fear that the formedinformation (two-dimensional bar code) may be deformed (melted) by theplating solution used in the exterior plating step. In this embodiment,however, since the two-dimensional bar code (BC2) is formed by stamping,there is no fear of the two-dimensional bar code (BC2) being deformed bythe plating solution even if the exterior plating is performed afterformation of the two-dimensional code (BC2).

<Lead Frame Cutting Step>

Next, the lead frame LF after completion of the above exterior platingis conveyed to a lead frame cutting step. In this step, as shown in FIG.16, unnecessary portions (tiebars 7 and outer frame portion 8) of thelead frame LF, which portions are exposed to the exterior of eachsealing body 10, are cut off. Subsequently, as shown in FIG. 17, theleads (outer leads) exposed to the exterior of the sealing body 10 areformed into a gull wing shape, whereby a QFP is completed.

Next, the two-dimensional bar code (BC2) of each QFP is read using a barcode reader (R6) shown in FIG. 1. The QFP not stamped with thetwo-dimensional bar code (BC2) on the surface of the sealing body 10 isremoved as a defective product and only the QFPs determined to benon-defective products are picked up and stored onto a tray.

<Testing Step>

Next, the QFPs stored as non-defective products on the tray are eachconveyed to a testing step, in which a burn-in test and an electricalcharacteristic test are conducted. In the burn-in test step, the QFP isloaded to a burn-in socket with use of a camera (C6) shown in FIG. 1,while in the electrical characteristic test, the QFP is loaded to a testsocket with use of a camera (C7).

Then, the two-dimensional bar code (BC2) of the QFP is read by a barcode reader (R7).

Further, correlation is made between test results and the identificationnumber of the QFP and the information thus obtained is stored in themain server (MS).

<Final Appearance Checking Step>

Next, each QFP determined to be a non-defective product in the abovetesting step is conveyed to a final appearance checking step. In thisstep, appearance check is made by image recognition using a camera (C8)shown in FIG. 1 to check whether there is a loss or deformation of leads5 (outer leads).

Then, the two-dimensional bar code (BC2) of each QFP is read using a barcode reader (R8). Further, the test results and the identificationnumber of the QFP are correlated with each other and the informationthus obtained is stored in the main server (MS).

The QFPs thus manufactured through the steps described above are shippedfrom the manufacturer to a customer, in which they are each mounted on apredetermined wiring substrate and then used. The shipping from themanufacturer to the customer is managed in correlation with the abovetwo-dimensional bar code (BC2).

In this embodiment the identification number (ID, two-dimensional barcode) is stamped to the outer frame portion 8 of the base member (leadframe LF) and is read in the molding step, then out of the pieces ofinformation (pieces of intra-server information) stored in the leadframe map data management server (LS), the information (intra-serverinformation) corresponding to the base member identification number(first identification number) thus read is encrypted as a newidentification number (ID, two-dimensional bar code) and thethus-encrypted identification number (second identification number) isput (formed) onto the sealing body 10.

In the case where a defect occurred in a completed semiconductor device(QFP) on the customer side after shipping of the QFP, the manufacturerreads with the bar code reader the two-dimensional bar code (BC2)stamped to the sealing body 10 of the defective QFP, thereby specifyingthe identification number of the QFP.

In the manufacturer's main server (MS), such pre-process information asfrom which production lot of semiconductor wafer the semiconductor chipsealed in each QFP was fabricated and at which position of thesemiconductor wafer it was located, is stored in correlation with theidentification number of the QFP concerned. Post-process informationsuch as under what conditions and by what manufacturing equipment eachQFP was manufactured, as well as corresponding operator information andthe materials used, in the above die bonding step, wire bonding step,molding step, tiebar cutting step, laser marking step, exterior platingstep, and lead frame cutting step, is also stored in the manufacturer'smain server in correlation with the identification number of the QFPconcerned.

Therefore, by reading the two-dimensional bar code (BC2) of each QFP tospecify the identification number of the QFP it is possible to trace inan instant the manufacturing conditions of the QFP stored in the mainserver (MS). As a result, it is possible to investigate the cause of adefect if any of a QFP quickly and hence possible to rapidly takemeasures against the defect recurring by feedback of the cause of thedefect to the manufacturing process.

The manufacturing method described above can be applied not only to ananti-defect measure for the QFPs shipped to customers, but also to ameasure against defects occurring in the course of manufacture. Morespecifically, if a defect of a QFP is found out during manufacture ofthe QFP, then by reading the two-dimensional bar code (BC1) stamped tothe lead frame LF concerned or by reading the two-dimensional bar code(BC2) stamped to the sealing body 10 concerned, it is possible to tracein an instant the manufacturing conditions in preceding steps of thesemi-fabricated product with that identification number put thereto andinvestigate the cause of the defect quickly in the course of themanufacturing process.

Although in this embodiment reference has been made to QFP as an exampleof a semiconductor package which is assembled using a lead frame, itgoes without saying that the present invention is applicable also toother semiconductor packages using a lead frame, e.g. QFN or TSSOP.

Second Embodiment

In this embodiment the present invention is applied to the manufactureof a CSP (Chip Size Package) which is a kind of a semiconductor package.FIG. 18 is an entire flow chart showing a manufacturing process for theCSP. As to the same contents, such as configuration, conditions andeffects, as in the first embodiment, explanations thereof will beomitted.

For manufacturing the CSP, first as base members (chip mountingmembers), there are provided a wiring substrate (map substrate) 20formed with a plurality of device areas such as that shown in FIGS. 19and 20, as well as a semiconductor wafer. FIG. 19 is an entire plan viewshowing a surface (upper surface, main surface) of the map substrate 20and FIG. 20 is an entire plan view showing a back surface (lowersurface, packaging surface) of the map substrate 20.

<On Map Substrate>

The map substrate 20 is a large-sized wiring substrate which serves as amatrix of a wiring substrate 25 of the CSP to be described later. Aplurality of wiring substrates 25 are obtained by dicing the mapsubstrate 20 lattice-like along dicing lines L indicated by dot-dashlines in FIG. 19. Along the dicing lines L the map substrate 20 ispartitioned in its long-side direction into six blocks and in itsshort-side direction into three blocks. Each of the blocks is an areawhich becomes one wiring substrate 25 after dicing the map substrate 20.Therefore, a total of 3×6=18 CSPs can be obtained from the map substrate20.

A large number of conductor patterns are formed of copper (Cu) in eachof the blocks of the map substrate 20. Of these conductor patterns,lands (electrode pads, bonding leads) 21 are illustrated in FIG. 19 andelectrodes (electrode pads, bump lands) 22 are illustrated in FIG. 20.

Though not shown, wiring lines coupled electrically to the lands 21 areformed on the surface of the map substrate 20. Those wiring lines arealso coupled electrically to the electrodes 22 on the back surface ofthe map substrate 20 through conductive members (via lines) formedwithin via holes which pierce through the map substrate 20. The surfaceof the map substrate 20 is covered with an insulating film (solderresist) except the area where the lands 21 are formed. Likewise, theback surface of the map substrate 20 is covered with an insulating film(solder resist) except the area where the electrodes 22 are formed.Surfaces of the lands 21 and electrodes 22 are each formed with aplating layer which is a laminated layer of, for example, a nickel (Ni)layer and a gold (Au) layer stacked on the nickel layer.

<On Semiconductor Wafer>

The semiconductor wafer used in manufacturing the CSP is not speciallylimited, but it is for example the semiconductor wafer 1A (see FIG. 3)used in the first embodiment. As noted above, the semiconductor wafer 1Ais divided into a large number of semiconductor chips 1. To eachsemiconductor chip 1 is put an identification number (ID) which includesinformation such as production lot number of the semiconductor wafer 1A,wafer number, the position of the semiconductor chip 1 in thesemiconductor wafer 1A, and whether the semiconductor chip 1 is anon-defective product or a defective product. The chip identificationnumber is managed by a server (wafer map data management server WS).

Next, a method for manufacturing the CSP according to this embodimentwill be described below step by step while making reference to theentire flow chart of FIG. 18, as well as FIGS. 21 to 28.

<ID Stamping Step>

First, a predetermined number of map substrates shown in FIGS. 19 and 20are provided. Then, as shown in FIG. 21, to a surface (upper surface,main surface) of an outer frame portion 8 of each map substrate 20 isstamped a two-dimensional bar code (BC3) corresponding to theidentification number (ID) of the map substrate 20. As shown in FIGS. 19to 26, the outer frame portion 8 of the map substrate 20 is an arealocated outside the foregoing eighteen blocks and outside each devicearea (an area where a sealing body 23 is formed) which will be describedlater.

For stamping the two-dimensional bar code (BC3) to the surface (uppersurface, main surface) of the map substrate 20 there is used a laserbeam (e.g., infrared light with a wavelength of about 1064 nm). Insteadof stamping with a laser beam, for example a seal with thetwo-dimensional bar code (BC3) printed thereon may be affixed to thesurface of the outer frame portion 8. Further, the same two-dimensionalbar code (BC3) may be stamped to plural positions of the outer frameportion 8, or in the case where the area of the outer frame portion 8 issufficiently wide, a one-dimensional bar code may be stamped in place ofthe two-dimensional bar code (BC3).

By thus stamping the identification number of the map substrate 20 inthe form of a bar code it is possible to automate specifying of theidentification number of the map substrate 20.

Next, using the bar code reader (RO) shown in FIG. 18, thetwo-dimensional bar code (BC3) stamped to each map substrate 20 is readand is stored in a map substrate data management server (BS). Now,preparations for recording the conditions in each step applied to thebase members corresponding to various identification numbers arecompleted in the map substrate data management server (BS).

Moreover, each map substrate 20 is subjected to an appearance check byimage recognition using the camera (CO). If a defect of a map substrateis detected, correlation is made between the identification number ofthe map substrate and the defective block and the information thusobtained is stored in the map substrate data management server (BS).

Thereafter, the surface of each map substrate 20 is subjected to plasmacleaning or chemical cleaning to clean the surfaces of the lands 21 andelectrodes 22. This is because, as noted above, an insulating film(solder resist) is formed on the surface of the map substrate 20 and acontaminant (outgas) is produced from the insulating film under theinfluence of heat which is induced by the radiation of a laser beam tothe base member (map substrate 20). In this embodiment, therefore, astep for cleaning the base member is provided after the ID stamping stepand before the die bonding step.

<Die Bonding Step>

Next, the map substrate 20 with the two-dimensional bar code (BC3)stamped thereon is conveyed to an apparatus (die bonding apparatus) usedin a die bonding step. Then, an adhesive (not shown) is supplied blockby block to the surface of the map substrate 20. Thereafter, as shown inFIG. 22, semiconductor chips 1 obtained from the semiconductor wafer 1Ashown in FIG. 3 are picked up one by one and each semiconductor chipthus picked up is mounted onto each block (chip mounting area).

When mounting the semiconductor chip 1 onto each block (chip mountingarea) of the map substrate 20, there is made alignment between thesemiconductor chip 1 and the block with use of the position recognizingcamera (C1) shown in FIG. 18. Moreover, the two-dimensional bar code(BC3) stamped to the map substrate 20 is read using the bar code reader(R1), and out of the pieces of base member information (pieces ofintra-server information) which were stored in the server (map substratedata management server BS) in a previous step (ID stamping step), theidentification number corresponding to the map substrate 20 recognizedby the bar code reader (R1) in the die bonding apparatus is drawn outfrom the interior of the server. Then, a check is made to see if thereis any defect in part of the map substrate 20 thus recognized. As aresult, if there is a defect in part of the map substrate 20corresponding to the identification number, the semiconductor chip 1 isnot mounted onto the block including the defect.

When mounting a semiconductor chip 1 onto each block of the mapsubstrate, reference is made to the identification number of thesemiconductor chip 1 stored in the wafer map data management server (WS)and a check is made to see whether the semiconductor chip 1corresponding to the identification number is a non-defective product ora defective product. If the semiconductor chip 1 is a defective product,it is not mounted onto the map substrate 20.

Next, correlation is made between the identification number of the mapsubstrate 20 obtained from the two-dimensional bar code (BC3) and theidentification number of the semiconductor chip 1 mounted onto the mapsubstrate 20 and the information thus obtained is stored in the server(main server MS). Further, correlation is made between the conditions(e.g., model number of the die bonding apparatus used and the kind ofthe adhesive) used at the time of mounting the semiconductor chip 1 ontothe map substrate 20 and the identification number of the map substrate20, and the information thus obtained is stored in the main server (MS).

In this way the semiconductor chip 1 is mounted onto each block of themap substrate 20 and correlation is made between the identificationnumber of each map substrate and the identification number of thesemiconductor chip 1 thus mounted on each map substrate 20, then theinformation thus obtained is stored in the main server (MS). Further,correlation is made between the conditions used at the time of mountingthe semiconductor chip 1 onto each block of each map substrate 20 andthe identification number of each map substrate 20, then the informationthus obtained is stored in the main server (MS).

<Wire Bonding Step>

Next, the map substrate 20 having gone through the above die bondingstep is conveyed to an apparatus (wire bonding apparatus) used in a wirebonding step. Then, the map substrate 20 is established in position ontoa stage of the wiring bonding apparatus. Thereafter, as shown in FIG. 23(a plan view showing a part of the map substrate 20 on a larger scale),the bonding pads 2 of the semiconductor chips 1 and the lands 21 of themap substrate 20 are coupled together electrically through conductivemembers 3. The conductive members 3 used in this embodiment are gold(Au) wires like those used in the first embodiment.

Next, the two-dimensional bar code (BC3) stamped to the map substrate 20is read using the bar code reader (R2), and out of the pieces of basemember information (pieces of intra-server information) stored in themap substrate data management server BS in a previous step (ID stampingstep), the identification number corresponding to the map substrate 20recognized by the bar code reader (R2) is drawn out from the interior ofthe server. Then, a check is made to see if there is a defect in part ofthe recognized map substrate 20. As a result, if a defect is found inpart of the map substrate 20 corresponding to the identification numberconcerned, wires 3 are not bonded to the lands 21 in the block includingthe defect.

Then, correlation is made between bonding conditions (e.g., model numberof the wire bonding apparatus used and the diameter of each wire 3) forthe wires 3 and the identification number of the map substrate 20obtained from the two-dimensional bar code (BC3) and the informationthus obtained is stored in the main server (MS).

In this way the bonding pads 2 of the semiconductor chips 1 mounted oneach map substrate 20 and the lands 21 are coupled together electricallyand correlation is made between the bonding conditions for the wires 3and the identification number of each map substrate 20, then theinformation thus obtained is stored in the main server (MS).

Thereafter, each map substrate 20 is subjected to an appearance check tocheck the wires 3 for breaking or short-circuit. In the event a defectis detected, correlation is made between the identification number ofthe associated map substrate 20 obtained from the two-dimensional barcode (BC3) and the block including the defect and the information thusobtained is stored in the map substrate data management server (BS).

<Molding Step>

Next, the surface of the map substrate 20 having gone through the wirebonding step (or the appearance check) is subjected to plasma cleaningand thereafter the map substrate is conveyed to an apparatus used in amolding step. Then, the map substrate 20 is disposed within a mold (notshown) of the molding apparatus and, where required, the two-dimensionalbar code (BC3) stamped to the map substrate 20 is read using moldingapparatus recognizing means (bar code reader R3), then out of the piecesof base member information (pieces of intra-server information) storedin the server (map substrate data management server BS) in a previousstep, the identification number corresponding to the map substrate 20recognized by the bar code reader (R3) in the molding apparatus is drawnout from the interior of the server.

Then, as shown in FIG. 24, the semiconductor chips 1, wires 3 and lands21 are sealed with molding resin to form a sealing body (resin sealingbody) 23. At this time, the device areas (the semiconductor chips 1mounted in the device areas) are sealed with resin such that theidentification number (two-dimensional bar code BC3) formed on the outerframe portion 8 is exposed to the exterior of the sealing body 23.Further, the filling performance of the resin is monitored using thecamera (C3) shown in FIG. 18. In this molding step, the semiconductorchips 1, wires 3 and lands 21 are sealed not block by block, but all theblocks are sealed at a time with resin. Consequently, the whole surfaceof the map substrate 20 except the outer frame portion 8 is covered withthe sealing body 23.

Next, the two-dimensional bar code (BC3) stamped to the outer frameportion 8 of the map substrate is read using the bar code reader (R3),thereafter, correlation is made between molding conditions (e.g., modelnumber of the molding apparatus used and the kind of the sealing body23) and the identification number of the map substrate 20 and theinformation thus obtained is stored in the main server (MS).

In this way each map substrate 20 is loaded to the mold of the moldingapparatus and the semiconductor chips 1, wires 3 and lands 21 are sealedwith resin. Further, correlation is made between the molding conditionsand the identification number of each map substrate 20 and theinformation thus obtained is stored in the main server (MS).

<Laser Marking Step>

Next, each map substrate 20 is put into a single wafer baking oven,allowing the sealing body to cure completely, and is then conveyed to anapparatus used in a laser marking step, in which two-dimensional barcodes (BC4) are stamped block by block to the surface of the sealingbody 23.

In this step of forming the two-dimensional bar codes (BC4), first thetwo-dimensional bar code (BC3) stamped to the outer frame portion 8 ofthe map substrate 20 is read using the bar code reader (R4) in the lasermarking apparatus. Then, out of the pieces of base member information(pieces of intra-server information) stored in the map substrate datamanagement server (BS) in a previous step, information (e.g.,intra-server information, chip position information, wafer productionlot number, semiconductor wafer number, assembly lot number, and productmodel name) corresponding to the map substrate 20 recognized by the barcode reader (R4) is drawn out from the interior of the server. Theinformation thus drawn out is formed as a new identification number(two-dimensional bar code BC4) on the surface side of the sealing body23. When stamping the two-dimensional bar codes (BC4) to the surface ofthe sealing body 23, marks (not shown) of product information (e.g.,product model name, customer logo mark, and production code) are alsostamped.

As to the information stored in the two-dimensional bar codes (BC4)formed on the surface of the sealing body 23, it is possible toselectively call the information managed by the server and let it bestored in the two-dimensional bar codes, with no limitation made to theforegoing information. Therefore, the information stored in thetwo-dimensional bar codes (BC4) may be the same information as thetwo-dimensional bar code (BC3) stamped to the outer frame portion 8 ofthe map substrate 20. In this case, after recognition using the bar codereader, by collating the information of the corresponding map substrate20 from among the pieces of base member information stored in the mapsubstrate data management server (BS), it is possible to draw out eachof the above pieces of information. In this embodiment, the conditionsfor the laser used in the laser marking step are the same as those usedin the ID stamping step, but no limitation is made thereto. Moreover,the method for forming the two-dimensional bar codes (BC4) is notlimited to the method using a laser beam. For example, seals having thetwo-dimensional bar codes (BC4) printed thereon respectively may beaffixed to the surface of the sealing body 23.

When stamping the two-dimensional bar codes (BC4) and marks, referenceis made to the map substrate data management server (BS) and a check ismade to see if a defect has occurred in part of the map substrate 20 inany of the past steps. If defects are found in part of the map substrate20, the two-dimensional bar code (BC4) and marks are not stamped to theblocks including the defects, as shown in FIG. 26.

Then, using the camera (C4), a check is made block by block to see ifthe two-dimensional bar code (BC4) and marks have been stampedpositively and the result of the check is stored in the main server (MS)while being correlated with the identification number of the mapsubstrate 20 concerned.

<Ball Mounting Step>

Next, the map substrate 20 having gone through the stamping step of thetwo-dimensional bar codes (BC4) and marks is conveyed to a ball mountingstep. Then, as shown in FIG. 27, solder bumps (ball electrodes) 24 asexternal coupling terminals of the CSP are coupled to electrodes 22formed on the back surface of the map substrate 20. In this case, astate of coupling between the electrodes 22 and the solder bumps 24 ischecked using the camera (C5) shown in FIG. 18 and the result of thecheck is stored in the main server (MS) while being correlated with theidentification number of the map substrate 20 concerned.

<Dicing Step>

Next, the map substrate 20 after completion of the coupling of solderbumps 24 is conveyed to a dicing step, in which it is diced along thedicing lines L shown in FIG. 19. When dicing the map substrate 20, thereis made alignment between a dicing blade and the map substrate 20 withuse of the camera (C6) shown in FIG. 18. In this way, as shown in FIG.28, there is completed a CSP wherein the semiconductor chip 1 mounted onthe upper surface of the wiring substrate 24 is sealed with the sealingbody 23 and with solder bumps 24 coupled to the back surface of thewiring substrate 25.

Then, the two-dimensional bar code (BC4) of each CSP is read using thebar code reader (R5) shown in FIG. 18. Further, the CSP with thetwo-dimensional bar code (BC4) not stamped to the surface of the sealingbody 23 is removed as a defective product and only the CSPs determinedto be non-defective products are picked up and stored on a tray.

<Testing Step>

Next, the CSPs thus stored as non-defective products onto the tray areconveyed to a testing step and are each loaded into a socket with use ofthe camera (C7) shown in FIG. 18, then are subjected to a burn-in testand an electrical characteristic test. Subsequently, the two-dimensionalbar code (BC4) of each CSP is read using the bar code reader (R6). Then,correlation is made between the test result and the identificationnumber of each CSP and the information thus obtained is stored in themain server (MS).

<Final Appearance Checking Step>

Next, the CSPs determined to be non-defective products in the abovetesting step are conveyed to a final appearance checking step. In thisstep, a state of coupling of solder bumps 24 is checked by imagerecognition using the camera (C8) shown in FIG. 18 and thereafter thetwo-dimensional bar code (BC4) of each CSP is read using the bar codereader (R7). Then, correlation is made between the result of thechecking and the identification number of each CSP and the informationthus obtained is stored in the main server (MS).

The CSPs thus manufactured through the various steps described above areshipped from the manufacturer to a customer, in which they are eachmounted for use onto a predetermined wiring substrate. The state ofshipping from the manufacturer to the customer is managed while beingcorrelated with the above two-dimensional bar code (BC4).

In this embodiment, the identification number (ID, two-dimensional barcode) is stamped to the outer frame portion 8 of the map substrate 20and is read in the molding step. Further, out of the pieces ofinformation (pieces of intra-server information) stored in the mapsubstrate data management server (BS), the information (intra-serverinformation) corresponding to the read identification number (firstidentification number) of the base member is encrypted as a newidentification number (ID, two-dimensional bar code) and the encryptedidentification number (second identification number) is put (formed) tothe sealing body 23.

In the event of occurrence of a defect in a completed semiconductordevice (CSP) after shipping, the manufacturer specifies theidentification number of the CSP by reading the two-dimensional bar code(BC4) stamped to the sealing body 23 of the defective CSP with use of abar code reader.

Pre-process information, such as from which product lot of semiconductorwafer the semiconductor chip sealed to the CSP concerned was obtainedand at which position of the semiconductor wafer the semiconductor chipwas located, is stored in the manufacturer's main server (MS) incorrelation with the identification number of the CSP. Post-processinformation, such as what conditions were adopted in the above diebonding, wire bonding, molding, laser marking, ball mounting and dicingsteps to manufacture the CSP concerned, is also stored in themanufacturer's main server in correlation with the identification numberof the CSP.

Thus, by reading the two-dimensional bar code (BC4) of each CSP andthereby specifying the identification number of the CSP it is possibleto trace in an instant the manufacturing conditions for the CSP storedin the main server (MS). Thus, the cause of the CSP defect can beinvestigated quickly, so that by feeding back the cause of the defect tothe manufacturing process it is possible to rapidly take measuresagainst the defect recurring.

Although the present invention has been described above concretely byway of embodiments thereof, it goes without saying that the presentinvention is not limited to the above embodiments, but that variouschanges may be made within the scope not departing from the gist of theinvention.

Although in the first and second embodiments described above thesemiconductor chips are mounted onto the chip mounting areas of the basemember in accordance with the wire bonding method, the mounting of thesemiconductor chips may also be done by a flip-chip method using bumpelectrodes as conductive members.

Although in the above embodiments a lead frame and a large-sized wiringsubstrate (map substrate) were used as examples of base members (chipmounting members), a TAB tape or a flexible wiring substrate is alsoemployable as the base member.

Although in the above first and second embodiments a laser was used tostamp the identification number (ID) to the base member and the sealingbody, there may be adopted a method which performs the stamping with useof a mold having such an end face as has a shape (two-dimensional barcode) corresponding to the identification number (ID) or a methodwherein a seal with the identification number (ID) printed thereon isaffixed to the base member and the sealing body. However, since theshape of the identification number (ID) differs for each base member,the method using a mold requires the provision of a mold correspondingto each base member (lead frame, wiring substrate). In the methodwherein a seal is affixed to the base member, there is a fear ofpeeling-off of the seal because a heating step for the base member isincluded in the post-process. Therefore, as a method for forming theidentification number (ID) it is preferable to use a laser as in theabove embodiments.

Although in the above first and second embodiments the identificationnumber (ID, two-dimensional bar code) is stamped to the base member andthe sealing body with use of a laser, the identification number may beprinted using special luminous ink adapted to emit light only whenirradiated with an electric illuminant (black light) which is filteredso as to emit only specific UV light (ultraviolet light). This printingmethod is an effective means in printing a two-dimensional bar codehaving information which is not to be made public carelessly. As notedabove, however, the plating step in the first embodiment follows thelaser marking step, so there is a fear that the printed special luminousink may be dissolved in the plating solution. For this reason it ispreferable that the identification number (ID, two-dimensional bar code)be formed using a laser.

Although in the above first and second embodiments the semiconductorchips 1 are mounted after the supply of an adhesive to the surfaces ofthe chip mounting areas, there may be adopted a method wherein a filmyadhesive layer is formed beforehand on the back surface of eachsemiconductor chip 1 (semiconductor wafer 1A) and then the semiconductorchip 1 is mounted onto the chip mounting area through the adhesivelayer.

Although in the above first and second embodiments die bonding isperformed in the die bonding step after making reference to theidentification information of the semiconductor chips stored in thewafer map data management server (WS), there may be adopted anothermeans. For example, according to another means for determining whethereach semiconductor chip 1 is a non-defective or defective product, adefect mark is formed on a defective product among the semiconductorchips 1 formed on the semiconductor wafer 1A. Next, in the die bondingstep, if this defect mark is recognized imagewise by the camera (C1)provided in the die bonding apparatus, the defective product is skippedand only non-defective semiconductor chips are mounted onto therespective chip mounting areas. Then, in this die bonding step, a chipidentification number (ID) is generated while making correlation withposition information of the semiconductor chip 1 concerned in thesemiconductor wafer 1A, information on non-defective and defectiveproducts, production lot number of the wafer and semiconductor wafernumber, and is stored in the wafer map data management server (WS). Thecorrelated information of both chip identification number (ID) and theidentification number of the base member (lead frame, wiring substrate)is also stored in the main server (MS). In this way, even aftercompletion of the semiconductor device, it is possible to easily specifyin which production lot a semiconductor chip 1 disposed within thesealing body was manufactured and in which semiconductor wafer and atwhich position the semiconductor chip 1 was located, by making referenceto the identification number formed on the surface of the sealing bodyor by making reference to both the said identification number and theinformation stored in the main server (MS).

Although in the above embodiments it has been described that variouspieces of information in the manufacturing process can be read by makingreference to the identification number (ID, two-dimensional bar code)formed on the sealing body, the said identification number may beutilized as an index mark. In case of using the identification number asan index mark, it is possible to omit the step for forming the indexmark separately from the identification number.

The present invention is applicable to the management of defectsgenerated in a semiconductor product manufacturing process.

1. A method of manufacturing a semiconductor device, comprising thesteps of: (a) providing a base member, the base member including adevice area having a chip mounting portion and an outer frame portionpositioned outside the device area; (b) after the step (a), putting afirst identification number to the outer frame portion of the basemember; (c) after the step (b), mounting a semiconductor chip over thechip mounting portion of the base member; (d) after the step (c),sealing the semiconductor chip with resin such that the outer frameportion is exposed, and forming a sealing body; and (e) after the step(d), reading the first identification number, and putting firstintra-server information corresponding to the read first identificationnumber, out of a plurality of pieces of intra-server information storedin a server, to the sealing body, as a second identification number. 2.The method according to claim 1, wherein the step (c) includes a step ofconveying the base member to a first apparatus, reading the firstidentification number with use of first recognizing means provided inthe first apparatus, drawing out the first intra-server informationcorresponding to the read, first identification number out of the piecesof intra-server information stored in the server, updating the firstintra-server information by correlating it with manufacturing conditionsin the step (c), and storing the updated first intra-server informationinto the sever.
 3. The method according to claim 2, wherein the step (d)includes a step of conveying the base member to a second apparatus,reading the first identification number with use of a second cameraprovided in the second apparatus, drawing out the first intra-serverinformation corresponding to the read, first identification number outof the pieces of intra-server information stored in the server, updatingthe first intra-server information by correlating it with manufacturingconditions in the step (d), and storing the thus-updated firstintra-server information into the server.
 4. The method according toclaim 3, wherein the step (e) includes a step of conveying the basemember to a third apparatus, and reading the first identification numberwith use of a third camera provided in the third apparatus.
 5. Themethod according to claim 4, wherein not only the second identificationnumber but also product information is put to the sealing body in thestep (e).
 6. The method according to claim 5, wherein a plating layer isformed over a surface of the base member after the step (e).
 7. Themethod according to claim 6, wherein the first and second identificationnumber are each formed by stamping with a laser.
 8. The method accordingto claim 7, wherein information different from the first identificationnumber is stored in the second identification number.
 9. The methodaccording to claim 8, wherein the first and second identificationnumbers are each a two-dimensional bar code.
 10. The method according toclaim 9, wherein the base member comprises a lead frame.
 11. The methodaccording to claim 5, wherein: the base member comprises a wiringsubstrate; and a surface of the wiring substrate is cleaned after thestep (b) and before the step (c).
 12. A method of manufacturing asemiconductor device bearing indicia from which information about amanufacturing history of the device can be ascertained, comprising thesteps of: (a) providing a base member, the base member including adevice area having a chip mounting portion and an outer frame portionpositioned outside the device area; (b) after the step (a), puttingfirst identifying information to the outer frame portion of the basemember; (c) after the step (b), mounting a semiconductor chip over thechip mounting portion of the base member; (d) after the step (c),sealing the semiconductor chip with resin such that the outer frameportion is exposed with the first identifying information still visible,and forming a sealing body; and (e) after the step (d), reading thefirst identifying information; (f) after the step (e), putting secondidentifying information on the sealing body, in response to reading ofsaid first identifying information, the second identifying informationbeing correlatable with information stored in one or more servers aboutthe manufacturing history of the semiconductor device.
 13. The methodaccording to claim 12, comprising: putting second identifyinginformation on the sealing body only if information indexed by the firstidentifying information indicates that there are no defects in thesemiconductor device.
 14. The method according to claim 13, comprising:cutting apart the sealing bodies; and removing as defective product,sealing bodies on which no second identifying information has been put.15. The method according to claim 12, comprising: updating at least oneserver with manufacturing condition information about one or more of thefollowing manufacturing steps: die bonding, wire bonding, molding,tiebar cutting, and laser marking, said manufacturing conditioninformation being associated with the first identifying information. 16.The method according to claim 12, comprising: updating at least oneserver with manufacturing condition information about one or more of thefollowing manufacturing steps: plating and cutting, said manufacturingcondition information being associated with the second identifyinginformation.